code: def _load_backend(backend: str) -> types.ModuleType:
      """
      Load a pandas plotting backend.
  
      Parameters
      ----------
      backend : str
          The identifier for the backend. Either an entrypoint item registered
          with importlib.metadata, "matplotlib", or a module name.
  
      Returns
      -------
      types.ModuleType
          The imported backend.
      """
      from importlib.metadata import entry_points
  
      if backend == "matplotlib":
          # Because matplotlib is an optional dependency and first-party backend,
          # we need to attempt an import here to raise an ImportError if needed.
          try:
              module = importlib.import_module(
                  "pandas.plotting._matplotlib"
              )
          except ImportError:
              raise ImportError(
                  "matplotlib is required for plotting when the "
                  'default backend "matplotlib" is selected.'
              ) from None
          return module
  
      found_backend = False
  
      eps = entry_points()
      key = "pandas_plotting_backends"
      # entry_points lost dict API ~ PY 3.10
      # https://github.com/python/importlib_metadata/issues/298
      if hasattr(eps, "select"):
          entry = eps.select(group=key)
      else:
          # Argument 2 to "get" of "dict" has incompatible type "Tuple[]";
          # expected "EntryPoints"  [arg-type]
          entry = eps.get(key, ())  # type: ignore[arg-type]
      for entry_point in entry:
          found_backend = entry_point.name == backend
          if found_backend:
              module = entry_point.load()
              break
  
      if not found_backend:
          # Fall back to unregistered, module name approach.
          try:
              module = importlib.import_module(backend)
              found_backend = True
          except ImportError:
              # We re-raise later on.
              pass
  
      if found_backend:
          if hasattr(module, "plot"):
              # Validate that the interface is implemented when the option is set,
              # rather than at plot time.
              return module
  
      raise ValueError(
          f"Could not find plotting backend '{backend}'. Ensure that you've "
          f"installed the package providing the '{backend}' entrypoint, or that "
          "the package has a top-level `.plot` method."
      )
  
imports: from __future__ import annotations
  import importlib
  from typing import TYPE_CHECKING, Callable, Literal
  from pandas._config import get_option
  from pandas.util._decorators import Appender, Substitution
  from pandas.core.dtypes.common import is_integer, is_list_like
  from pandas.core.dtypes.generic import ABCDataFrame, ABCSeries
  from pandas.core.base import PandasObject
label_desc: Use image node_id 6 for calling a global function with example usage: _load_backend(backend) and returns: module, module